AP Photo/Natacha PisarenkoMichael Jackson fans attend a vigil in Buenos Aires, on Friday. The 50-year-old pop star died Thursday, just as he was preparing for a series of 50 concerts starting July 13 at London's 02 arena.

MEXICO CITY -- Michael Jackson imitators moonwalked at Mexico's Angel of Independence, a prison in the Philippines organized a "Thriller" tribute dance, political leaders paid homage and French fans gathered at Notre Dame to sing and cry as the world mourned the King of Pop.

From Paris to Peru, tributes both personal and public were held Friday by generations of fans, from those who danced to "ABC" and hummed along with "I'll be There" and "Ben" in the '70s, to the Generation X'ers who moonwalked and gyrated to "Billie Jean," ''Thriller" and "Bad" in the 1980s.

In Mexico City, a half-dozen 20-something fans took turns busting Jackson-like moves on the steps of the country's iconic Angel of Independence monument and later sat arm-in-arm holding candles and posterboards covered with Jackson photo collages and heartfelt messages.

"I love you Michael Jackson, King of Pop," said one. "I will love you forever."

One member of the small gathering, Oliver Munoz, tried to moonwalk his sadness away as he fondly remembered his 20-year membership in a local Jackson fan club.

"At first it's kind of like being in shock," he said. "It doesn't soak in. But then later you really start to feel the sadness and you just give in to the tears."

In one of Mexico City's hundreds of busy nightclubs Thursday evening, a DJ interchanged standard techno-music and hard rock with Jackson songs including "Beat It" and "Billie Jean," while clients sadly raised their glasses in a toast.

Throughout Latin America, fans planned weekend tributes in town squares, while in Paris on Friday hundreds of Jackson fans sang, danced, cried and shouted out in grief at a gathering in front of the Notre Dame cathedral.

In London, shocked fans united at the Lyric Theatre, where a live show based on Jackson's record-selling album "Thriller" is being performed, and waited for news about refunds for 750,000 tickets to his sold-out, 50-night run.

In the Philippines, prison security consultant Byron Garcia planned a tribute for Jackson on Saturday with inmates performing an encore of a famous video in which they do a synchronized dance to "Thriller." The video has had 23.4 million hits on YouTube.

"My heart is heavy because my idol died," Garcia said.

Newspapers around the world covered their front pages with pictures of Jackson, who publicly morphed from a bellbottom-wearing child star to a pale-skinned, thin-nosed man with lipstick, eyeliner, and a troubled personal life.

Many Japanese TV channels switched to special programming while Mexico's TV Azteca invited Jackson imitators to participate in a special program it will devote to the entertainer in coming days.

One such impersonator, Uruguayan singer Jorge Drexler, performed a duo, acoustic version of "Billie Jean" with Mexican actress and singer Ximena Sarinana on Thursday night in Mexico.

"I am sad," Drexler was quoted by El Universal newspaper as saying. "I danced a lot with him (Jackson) when I was a kid."

Fans snatched up recordings of Jackson's music around the world: A major Japanese online retailer was flooded with orders for Jackson's recordings, and music stores in Mexico City's touristy Pink Zone had sold out of his compact discs.

"Sales have been impressive," said Ana Reinish, marketing manager for the Mexican music chain Mixup, without elaborating. "I'm sure it's going to break records, more than for any other artist who has died. We've never seen anything like this."

Jackson's death also caused a commotion in cyberspace, where it dominated social networking sites on which users only days earlier had focused on and supported the rise of the Iranian opposition.

But at least one expert says it is dangerous to draw any connection between a drop in Iran-related tweets and the weakening of the opposition.

"If you are a cleric in Iran wishing for the international community to stop paying attention to this extraordinary story in your back yard, you are certainly glad for this distraction" of Michael Jackson's death, said John Palfrey, a Harvard Law School professor and faculty co-director of Harvard's Berkman Center for Internet & Society.

"But I would be very careful about giving it a sense of cause and effect: 'The Michael Jackson story has risen on Twitter and Iran has fallen and therefore'" it has negatively affected the opposition movement.

"That's an extraordinary overstatement," he said.

Governments from around the world recognized Jackson's passing, with former South Korean President Kim Dae-jung, who had met the singer, remarking that "We lost a hero of the world."

Mexican President Felipe Calderon made a reference to Jackson during a ceremony commemorating the international day against illegal drug use and trafficking saying, "What a paradox today that ... one of the greatest idols of several generations and the largest seller of pop music died precisely because of this ... excessive use of drugs."

In fact, the official cause of Jackson's death has not been determined and is not expected to be known for weeks, although Brian Oxman, a former Jackson attorney and a family friend, told NBC's "Today" show Friday that he had been concerned about Jackson's use of painkillers and had warned the singer's family about possible abuse.

In November 1993, Jackson canceled the rest of his "Dangerous" world tour to seek treatment for addiction to painkillers prescribed after reconstructive scalp surgery.

Whatever led to Jackson's death, his passing left a deep impression on fans and fellow singers worldwide.

"Michael Jackson was the king of artistic brilliance," Colombian pop star Shakira said in a statement. "With his death ... a legend is born that will last until the end of time."